The present invention relates to an improvement of a granule transfer apparatus and a granule spreading method, used to transport and place fresh concrete for dams, building structures, etc., transport and spread mortar, or transport and spread earth and sand for reclamation.
A transfer apparatus for fresh concrete or the like, which comprises a tower mast, a stage, a boom body formed of two or more boom components, etc., is a generally known apparatus described in an international application (WO96/16242) that is subjected to international publication, for example.
Referring now to FIG. 17, there will be described an outline of this conventional concrete transfer apparatus.
A tower mast TM contains therein a vessel-shaped carrier CV for pulling up fresh concrete F (concrete not hardened) from a concrete plant or the like onto an elevator body portion EL through the space under the tower mast TM. The vessel-shaped carrier CV is pulled up by means of a lift winch 171 with the aid of a wire rope 170. The lift winch 171 is fixed to a stage body portion 172 that constitutes the elevator body portion EL.
Supported on the stage body portion 172 is a boom body portion, which is formed of a first boom component Cxe2x80x2 and a second boom component Cxe2x80x3.
The fresh concrete, pulled up to the upper part of the tower mast TM by means of the vessel-shaped carrier CV, is fed onto a conveyor for fresh concrete transportation (belt conveyor Gxe2x80x2), which is provided on the first boom component Cxe2x80x2 on the stage body portion 172, via fresh concrete delivery means 173 and 173xe2x80x2.
The proximal end of the second boom component Cxe2x80x3 is connected to the distal end of the first boom component Cxe2x80x2, and these boom components Cxe2x80x2 and Cxe2x80x3 are arranged continuous with each other, in front and in rear, on a straight line. The first boom component Cxe2x80x2 is provided with pulleys 174 and 175 on its opposite ends, individually, and the first belt conveyor Gxe2x80x2 is stretched between the pulleys 174 and 175. The first belt conveyor Gxe2x80x2 is driven by a belt conveyor drive motor 176 that is placed on the first boom component Cxe2x80x2. The second boom component Cxe2x80x3 is provided with pulleys 177 and 178 on its opposite ends, individually, and a second belt conveyor Gxe2x80x3 is stretched between the pulleys 177 and 178. The second belt conveyor Gxe2x80x3 is driven by a belt conveyor drive motor 179 that is placed on the second boom component Cxe2x80x3.
The fresh concrete F, which is fed onto the first belt conveyor Gxe2x80x2 via the fresh concrete delivery means 173 and 173xe2x80x2, is transported away from the stage body portion 172 by the first belt conveyor Gxe2x80x2 and delivered onto the second belt conveyor Gxe2x80x3. The fresh concrete on the second belt conveyor Gxe2x80x3 is further transported away from the first belt conveyor Gxe2x80x2 and dropped onto the ground through the distal end of the second belt conveyor Gxe2x80x3.
An upper lift frame 180 is fixed to the stage body portion 172, while a lower lift frame 182 is fixed to a mast frame 181 of the tower mast TM. A hydraulic cylinder 183 is interposed between the upper and lower lift frames 180 and 182 so that the upper lift frame 180 or the stage body portion 172 can be lifted or lowered with respect to the lower lift frame 182 or the tower mast TM.
The first boom component Cxe2x80x2 can be turned on a substantially horizontal plane with respect to the stage body portion 172 by means of a boom turning device 184. Further, the drawn-up length of the second boom component Cxe2x80x3 from the first boom component Cxe2x80x2 is adjustable so that the overall transportation length that combines the first and second belt conveyors Gxe2x80x2 and Gxe2x80x3 can be changed. Accordingly, the point on which the fresh concrete drops through the distal end of the second belt conveyor Gxe2x80x3 is settled depending on the angle of turn of the first boom component Cxe2x80x2 (and second boom component Cxe2x80x3) with respect to the stage body portion 72 and the drawn-up length of the second boom component Cxe2x80x3 from the first boom component Cxe2x80x2.
If the drawn-up length of the second boom component Cxe2x80x3 from the first boom component Cxe2x80x2 is reduced, however, the position of the distal end of the second belt conveyor Gxe2x80x3, from which the fresh concrete drops, gets nearer to the tower mast TM, but, it never gets beyond the position of the distal end of the first boom component Cxe2x80x2 as it approaches the tower mast TM. Thus, the fresh concrete cannot be dropped on any region near the tower mast TM by only making a combination of the first and second boom components Cxe2x80x2 and Cxe2x80x3 turnable on a substantially horizontal plane with respect to the stage body portion 172 and making the substantial length of the combination of the first and second boom components Cxe2x80x2 and Cxe2x80x3 changeable.
To solve this problem, a tripper device H is provided on the first boom component Cxe2x80x2 so as to be movable with respect to the first boom component Cxe2x80x2. The tripper device H enables the fresh concrete, delivered thereto by means of the first belt conveyor Gxe2x80x2 on the first boom component Cxe2x80x2, to be taken out sideways and dropped on the way. If the tripper device H is situated on the distal end of the first boom component Cxe2x80x2, the fresh concrete delivered thereto by means of the first belt conveyor Gxe2x80x2 is fed onto the second belt conveyor Gxe2x80x3 on the second boom component Cxe2x80x3 without being taken out sideways. Accordingly, the point on which the fresh concrete drops from the tripper device H is settled depending on the angle of turn of the first boom component Cxe2x80x2 with respect to the stage body portion 172 and the position of the tripper device H on the first boom component Cxe2x80x2.
Thus, the conventional fresh concrete transfer apparatus shown in FIG. 17 has the following problems.
(1) Since the first and second boom components Cxe2x80x2 and Cxe2x80x3 turn on the horizontal plane with respect to the stage body portion 172 in a manner such that they are arranged continuous with each other, in front and in rear, on a straight line. It is necessary, therefore, to secure a wide area around the tower mast TM that is free from obstacles.
(2) The fresh concrete can be dropped in zigzags onto the ground by gradually moving in the distal end of the second boom component Cxe2x80x3 in the dropping position or the tripper device H on the first boom component Cxe2x80x2 in a certain direction while alternatingly turning the stage body portion 172 itself that is fitted with the first and second boom components Cxe2x80x2 and Cxe2x80x3. However, the heavyweight structure that includes the first and second boom components Cxe2x80x2 and Cxe2x80x3 and the stage body portion 172 has a great inertial mass, so that there is a problem on response when its movement is controlled for fine operation, in particular.
(3) Further, the structure in which the second boom component Cxe2x80x3 is connected to the distal end of the first boom component Cxe2x80x2 in a straight line requires the structure of the second boom component Cxe2x80x3 to be designed for lighter weight. Accordingly, the second boom component Cxe2x80x3 or the junction between the first and second boom components Cxe2x80x2 and Cxe2x80x3 is liable to suffer a problem in rigidity.
In order to solve this problem, the boom on the distal end side (second boom component Cxe2x80x3) may be suspended from the tower mast TM in a manner such that one and the other ends of a suspension rope are fixed to the boom on the distal end side and the upper part of the tower mast TM, respectively. Since the boom components are contractible as mentioned before, however, the length of the suspension rope cannot be fixed. It is necessary, therefore, to change the length of the suspension rope as the boom is extended or contracted or give up attaching the suspension rope itself. Inevitably, the former arrangement requires use of a winch or other equipment that entails a complicated construction. If the attachment of the suspension rope is given up, on the other hand, the problem on rigidity cannot be solved.
(4) Further, the connected boom components are restricted in number by the aforesaid structural problem. Practically, the number of connectable boom components is limited to two (first and second boom components Cxe2x80x2 and Cxe2x80x3) , as shown in FIG. 17. In the case where the combined boom in its minimum-length state is not very short and if the transfer apparatus is located in a narrow space, the mobility of the apparatus is restricted substantially.
(4) In the case where the combined boom body is supported on the tower mast that is built on the ground, moreover, the fresh concrete or the like can be spread and placed only in the region around the tower mast.
The object of the present invention is to provide a granule transfer apparatus and a granule spreading method utilizing the granule transfer apparatus, which eliminate the aforementioned drawbacks of the prior art, and in which granule can be spread around a boom body supporting portion, such as a tower mast, without use of a tripper device, the granule can be spread without shifting the location of the boom body supporting portion such as the tower mast even in case there are any obstacles between a target position for spreading operation and the boom body supporting portion such as the tower mast, weaving operation can be smoothly effected in various directions, the rigidity of a boom component on the distal end side and its junction can be secured satisfactorily, and a boom body can be designed so that its minimum-state length is shorter than that for the conventional apparatus.
Further, the boom body supporting portion is attached to a traveling body, such as a vehicle or vessel, so that a granule spreading region can be selected freely.
In order to achieve the above object, a granule transfer apparatus according to the present invention is a granule transfer apparatus that comprises a boom body formed of two or more connected boom components each including transfer means for transferring granule, a boom body supporting portion for rotatably mounting a stage having the boom body, stage turning means for turning the stage relatively to the boom body supporting portion, and granule delivery means provided on the stage and serving to deliver the granule to the transfer means of the boom component situated nearest to the stage. The granule transfer apparatus further comprises a pivotal portion located between the two connected boom components and serving to connect the basal part of the next boom component to the distal end portion of the boom component on the stage side, boom turning means for turning the next boom component with respect to the stage-side boom component, and junction granule delivery means for delivering the granule from the transfer means of the stage-side boom component to the transfer means of the next boom component.
In an aspect of a granule spreading method according to the present invention using one such granule transfer apparatus, an operational movement program to order the position of the boom body end and a rectilinear or arcuate movement between positions is previously taught, and the controller is caused to drive the transfer means to move the boom body end along a movement path given by the taught program and spread the granule while throwing out the granule through the boom body end, in accordance with the taught program.
In another aspect of the granule spreading method, the control means is previously caused to set and store a movement pattern for the boom body end, a granule spreading region is set as an input in the control means to move the boom body end into the granule spreading region, and the transfer means is then driven to move the boom body end in the set granule spreading region, thereby automatically spreading the granule, in accordance with the set movement pattern, while the granule is being thrown out through the boom body end.
According to the granule transfer apparatus of the present invention and the granule spreading method using this granule transfer apparatus, fixed-position rotation of the stage and turning motion of each boom component are combined so that the granule can be spread all over the peripheral region of the boom component supporting portion (tower mast and traveling body), so that boom components need not be provided with a tripper device thereon. Thus, the construction of the granule transfer apparatus is simplified, so that the general manufacturing cost is reduced. As the weight is reduced, moreover, the rigidity and strength of the boom body are improved relatively.
Moreover, the angle of turn of the stage and the angle of turn of each boom component can be adjusted without changing the target spreading position for the granule. If there are any obstacles between the boom body supporting portion, such as the tower mast, and the target spreading position, therefore, the granule spreading operation can be carried out without making any large-scale rearrangement, such as relocation of the boom body supporting portion such as the tower mast.
Further, tamping operation based on weaving can be carried out with only the boom component in the leading position rocked bit by bit. Therefore, the tamping operation can be effected more quickly and smoothly than in the case of the conventional apparatus in which the weaving operation is performed by continuously extending and contracting the continuous boom body on a straight line or by alternatingly turning the stage bit by bit. Since the granule can be automatically spread over the set granule spreading region in accordance with the taught pattern, the tamping operation can be carried out easily. Furthermore, the granule can be automatically spread along a taught granule spreading path.
Since the substantial lengths of the boom components are subject to no change, moreover, the strength of each boom component and its pivotal portion can be secured with use of a very simple structure including a suspension rope, mast, etc., and the rigidity of the whole boom body can be improved. Furthermore, the rigidity can be secured without increasing the weight or complicating the construction. If the same rigidity of the boom body as in the conventional case is required ultimately, therefore, the boom body can be dividedly composed of more boom components and can be designed so that its minimum-state length is shorter than that for the conventional apparatus.